A number of systems and programs are offered on the market for the design of parts or assemblies of parts, such as the one provided by DASSAULT SYSTEMES under the trademark CATIA. These so-called computer-aided design (CAD) systems allow a user to construct and manipulate complex three-dimensional (3D) models of objects or assemblies of objects. CAD systems thus provide a representation of modeled objects using edges or lines, in certain cases with faces. Lines or edges may be represented in various manners, e.g. non-uniform rational B-splines (NURBS). These CAD systems manage parts or assemblies of parts as modeled objects, which are essentially specifications of geometry. Specifically, CAD files contain specifications, from which a geometry is generated, and from geometry a representation is generated. Specifications, geometry and representation may be stored in a single CAD file or multiple ones. CAD systems include graphic tools for representing the modeled objects to the designers; these tools are dedicated to the display of complex objects—the typical size of a file representing an object in a CAD system being in the range of a Mega-byte for part, and an assembly may comprise thousands of parts. A CAD system manages models of objects, which are stored in electronic files.
There also exist product life cycle management solutions (PLM), such as the one provided by DASSAULT SYSTEMES under the trademarks CATIA, ENOVIA and DELMIA; these solutions provide an Engineering Hub, which organizes product engineering knowledge, a Manufacturing Hub, which manages manufacturing engineering knowledge, and an Enterprise Hub which enables enterprise integrations and connections into both the Engineering and Manufacturing Hubs. All together the systems deliver an open object model linking products, processes, and resources to enable dynamic, knowledge-based product creation and decision support that drives optimized product definition, manufacturing preparation, production and service. Such PLM solutions comprise a relational database of products. The database comprises a set of textual data and relations between the data. Data typically include technical data related to the products, said data being ordered in a hierarchy of data and are indexed to be searchable. The data are representative of the products, which are often modeled objects.
One of the problems in such PLM solutions is that the users of the system may wish to display the products and have a three dimensional graphic representation of the products. DASSAULT SYSTEMES provides under the name DMU Review a series of CAD tools for allowing the user of PLM solution to handle a three dimensional graphic representation of the products managed in the system. These tools rely on the use of digital mock-ups which are pre-computed from CAD representations of the products. These tools further provide a restricted set of graphic views of the products; specifically, as explained below in reference to FIG. 1, the DMU systems usually provide a three-dimensional representation of the products. In the system sold under the name DMU Navigator, the user may display a three dimensional representation of a complex product; the display further comprises a hierarchical tree representing the various products or parts of said displayed product. FIG. 1 is a view of a display in DMU Navigator. On the left hand side of the display appears a tree 2 which is representative of the database content. As represented in FIG. 1, the root level of the tree designates a complete assembly—in the example of FIG. 1, a car. The next level of the tree shows a series of subassemblies composing the root level product—the Conditioning System, the Engine, the Body, the GearBox, the Pedal System etc. There is also provided a series of applications. The display further shows a three dimensional representation of the product. The user may click on one of the subassemblies in the tree—for instance the Pedal System—and the system will then display a three dimensional representation of the selected subassembly. The user may expand the corresponding branch in the tree—by clicking on the “+” sign left of the subassembly for displaying the parts which compose a subassembly—for instance, the Braking Pedal in the Pedal System. Selecting one of the parts will again cause the system to display a three dimensional representation of the relevant part.
This system provides to the user three-dimensional representations of the products stored in the database. However, navigation in this system may still be improved. With CAD tools such as DMU review or DMU Navigator, the user is only able to navigate among the parts or the products that have been loaded in the system. Therefore, the scope of the navigation is very limited since if the user wishes to navigate among all the available products or assemblies, he has to load all those products or assemblies, which is impossible due to hardware constraints and transactions issues.
As a matter of fact, DMU products are limited with regards to the scope of navigation. Specifically, the user first opens a DMU session, where a limited list of parts and assemblies is defined. This makes it possible for the system to compute and store the representations that will thereafter be used in the DMU navigation. Navigation is limited to the list of parts and assemblies defined when the DMU session is opened.
Furthermore, the user may wish to know where the above mentioned Braking Pedal is also used, i.e. in which other models of car it is embedded. Actual CAD tools enable a user to navigate between parts or products mainly according to the “is composed of” relation. Databases used in Product Data Management (PDM) systems enable the user to make queries on all types of relation between parts or product and the scope of navigation of the databases is the widest possible. As a matter of fact, the user can have access to all the parts, products or assemblies.
Nevertheless, databases do not allow the user to easily navigate since the data do not have a graphical representation. Data are identified by file names or types and those names may not be relevant enough to identify precisely the items that the user is looking for.
Thus, there is a need for a solution allowing a user to navigate in a relational database representing modeled objects, especially in a database of products in a product lifecycle management system. The solution should preferably be user-friendly and should allow the user to locate and display products in an easy and intuitive way.